This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2000-044582, filed Feb. 22, 2000, the entire contents of which are incorporated herein by reference.
The present invention relates to a computer having a connection interface device to extend various functions, an extension unit for extending various functions of the computer, an interface circuit connected between the computer and the extension unit and a computer system.
There is a computer system comprising a computer and an extension unit connected to the computer for extending various functions of, for example, a serial port, a printer port, a PC card, etc. In such a computer system, the computer is connected to the extension unit via a connector. The connector has the lines each of which corresponds to the interface signals required for the various functions.
In such a conventional connection interface device, since the size of the connector depends the number of interface signals directly, it is difficult to reduce the size of the computer.
On the contrary, according to an another conventional computer system, by providing plural types of extension units with limited extension functions (extension unit for PC card, serial port, extension unit for printer port, etc., for example) or by providing plural types of extension units with single function, the size of an extension connector of a computer is reduced, so that the computer itself can be made compact.
However, since extension functions of individual extension units are significantly limited in such functional extension constitution, all the extension functions can not be used simultaneously. In addition, since it is necessary to select an extension unit corresponding to each extension function, which is inconvenient to use and economically disadvantageous for uses.
An object of the present invention, which has been achieved in view of the above-noted problems inherent in the prior art, is to provide a computer can use plural extension functions and be made compact without lowering operational speed.
According to an aspect of the present invention there is provided a computer system comprising a computer; an extension unit for connecting a peripheral equipment to extend functions of the computer; an interface circuit for connecting between the computer and the extension unit; wherein the computer includes: a generator for generating data signals and control signals transmitted to the peripheral equipment; a parallel-serial converter for converting the data signals to serial data signals and serial-transmitting the serial data signals to the extension unit via the interface circuit and a controller for transmitting the control signals in synchronization with the a conversion operation of the parallel-serial converter; the extension unit includes a serial-parallel converter for converting the serial data signals to parallel data signals and transmitting the parallel data signals to the peripheral equipment.
According to another aspect of the present invention there is provided a computer comprising: a generator for generating data signals and control signals transmitted to a peripheral equipment; a parallel-serial converter for converting the data signals to serial data signals and serial-transmitting the serial data signals to a serial-parallel converter, which is arranged in an extension unit for connecting the peripheral equipment to the computer, converts the serial data signals to parallel data signals and transmits the parallel data signals to the peripheral equipment; and a controller for transmitting the control signals in synchronization with the a conversion operation of the parallel-serial converter.
According to another aspect of the present invention there is provided a extension unit, the extension unit connecting between a computer and a peripheral equipment, comprising: serial-parallel converter for converting serial data signals generated by the computer to parallel data signals and transmitting the parallel data signals to the peripheral equipment; and a bus for transferring control signals generated by the computer to the peripheral equipment.
According to another aspect of the present invention there is provided a interface circuit, the interface circuit connecting between a computer and an extension unit connected a peripheral equipment, comprising: a first line for transferring serial data signals generated by the computer to serial-parallel converter, which is arranged in an extension unit for connecting the peripheral equipment to the computer, converts the serial data signals to parallel data signals and transmits the parallel data signals to the peripheral equipment; a second line for transferring control signals generated by the computer to a peripheral equipment via the extension unit; and a third line for response signals generated by the peripheral equipment in response to the control signals.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.